When I worked in a condensed matter physics lab, I touched a quartz tube recently heated by an oxy-hydrogen torch. Burned my thumb! Fortunately, it was only superficial.
I did this on accident also, my skin turned white. Luckily it was only a tiny spot and after the blister and new skin you can nearly notice it anymore. The funny thing about the experience for me is I didn't feel it at the second it happened, and the pain just got gradually worse after I realized. It probably got to peak pain about 10 minutes after. The body is strange the way it works. Pretty amazing really.
I was touching red hot pen springs for fun. Quite an experience! No pain, only parallel lines burnt into my fingers, pretty interesting way to modify fingerprints.
I touched a hot plate which was turned on, because i thought it was off. I got near it first to test if its on, didnt feel the heat somehow (maybe it was going on and off and at that moment it was off), and to be sure that its off i touched it. Instantly retracted my hand. This left a white powder on the surface of my hand. Luckily only the very top layer got burned to dust, and the below layers where fine.
In the end, it turned out that the entire clip was just an advertisement, even the part before it, and everything was just an opening or context to introduce the product.
Two different proceses: first the IR cameria is simply making an inference between light emission & temperature & its based up on limited IR spectrum, not the full light spectrum. Visible light has a correspondence with much higher temperatures than IR, but the thermal camera does not interprete white light with heat. When you shine a high watt light source on a object that absorbs the light, the light stimulates the electrons in the object causing increase molecular viberations (ie heat).
One big issue I have with science communication is the oversimplification tends to always fall into epistemic fallacies. When you say things like "This curve is determined by Planck's Law" it implies it has agency or causal power, it conflates our knowledge of the universe with the actual mechanisms. Scientific laws are frameworks for understanding observations, not the "causes" of phenomena. A very common example is when people say a particle knows when it's being observed in a quantum system. Particles don't possess awareness or agency, it's is the act of measuring that interacts with a quantum system. I don't mean to target this directly at The Action Lab, these are just thoughts I've had for some time now.
Nah, you're looking too deep into it. Anyone with basic education understands that it's not the Planck's Law that forces things to emit in a particular way, it's their emission spectrum is distributed according to some law. Also it's appropriate to say exactly as stated in the video, because he was talking about the CURVE, which is a mathematical object described by the Planck's Law. It doesn't exist in reality as well.
Sixty Symbols did a video on this topic 11 years ago called "Negative Temperatures are HOT" referring to negative absolute temperatures rather than negative Fahrenheit or Celsius. You can also think of them as beyond infinite temperature. Heat will _always_ move from a negative temperature region into a positive temperature region no matter how hot the positive temperature is. You can literally heat the Sun a minuscule amount by shining a laser at it.
This is a great video, I design laser engraving systems. We go down to spots with a size of a few microns to get some enormous power density. This is a great basic video explaining some of the phenomenon
I learned yesterday that we figured out what was diamonds were by vaporizing them, and then doing experiments to see what the gas was! This was in the 1700s! One of the methods they used was simply lenses. How crazy is that. I've seen people burn rocks, but diamonds just using the sun is crazy to me. He should do this himself. Makes me appreciate glass. Where would science be without it. They used glass lenses to vaporize diamond to capture the gas in glass vessels to weigh the gas! Then used glass beakers to do the tests.
What confuses me is the sun is continually adding energy - it's an ongoing nuclear reaction continuously pumping more energy out in the EM spectrum - it's not coherent light like a laser, but there's not only the blackbody light radiation coming from the sun, but all of the photons generated by nuclear fusion as well - so it should theoretically be able to do what a laser pointer does a trillion times over.
The light coming from the sun is not the light emitted in the fusion reactions in the core. Light takes thousands of years to get out of the core to the surface.
not true, coherence matters, the sun radiation can not heat up a body to temperatures higher than the sun surface temperature of 5000 °K otherwise it would contradict thermodynamics second law. A laser pointer can go higher given the absorbing object is insulated enough.
for that same reason we can not infer what really is the temperature of the sun, as the law we use to calculate temperature from radiation only applies to objects in thernal equilibrium.
The laser light is transferring energy. Whatever the laser is shining on is accumulating that energy so it is a question of time and energy not simply energy.
The video feels incomplete, light goes in and the light-matter interaction is where all the black box magic lies, but this video didn't explain that. Would that same laser melt me up like it did the metal? Why or why not? How does the energy of the laser get converted into thermal energy? The material absorbs it, and how much it's absorbed is material-dependent, why? What's the difference between a continuous wave laser and a pulsed laser?
5:27 Question: how does LASER compare to SOLAR radiation? I think of the sun as emitting all manner of spectrum, based on something somebody said about Parker space probe data result ... What is the EM difference of focused LASER vs solar, thinking a minuscule Earth sized critter is in a straight line to the solar radiance, thus reasonably coherent beams of photons??? Just wondering 'bout Black Body radiation vs EM ... the rest was very educational, but caused me this question about exceeding limits. If a lens focused a particular wavelength, continually powered by the sun, how would the physical interaction effect result differently, laser vs specific solar radiation? (if the lens were focused in outer space without pesky atmospheric light scattering annoyance 😬) EDIT: I will search "what happens if you focus a laser Action Lab" based upon a comment.
Man that laser is so satisfying seeing it cut that thick metal like it's nothing! This is a great approach to heating things up. The way lasers & magnetrons heat things up reminds me of how Tesla considered we could destroy anything if we manipulate the objects frequency in order to vibrate it until it breaks apart. So take that but shift it over to an electromagnetic device that manipulates a large amount of electrical energy and aim it at a focused point and allow the electromagnetic frequencies to interact with that object until it heats it up
Thanks! I needed this video to explain how that little laser of only a couple of milliwatts somehow managed to heat the parts of the radiometer all the way to incandescence! 🔥
8 часов назад+1
You can heat metallic things with "radio wave" frequencies using induction furnace...
A laser differs from a regular light in the fact that it is monocromatic, coherent, and directional.. so, how can a laser be able to heat something to infinity while a concentrated regular light only can heat something up till it gets to the temperature of the source of that light?? What is the difference in the business end of the light, when impacts a surface?... I wonder..
This is exactly my question. The video didn't really explain why laser light is different. Perhaps the coherence of the light is the big difference here? You could surely filter out all the frequencies of sunlight to a single frequency, and concentrate it.... but you couldn't make it coherent.
@@stevesether It kept me thinking, could it be that "light transferring energy" behave as heat or electric current?, where you have "temperature" and "heat" or "voltage" and "current" respectively.. let's say.. an impulsory force and an ammount of energy being transfered.. once the force is in equilibrium you can't "push" anymore energy to the other side... Laser might have, or be able to get, an arbitrarily high level of "force" to "push" while for sunlight or any random white light the "force" is only as strong as for the source of that light, so it cannot achieve higher temperatures. In such a case, what would be the "voltage" (or pressure making a fluids analogy) for the light? I don't know..
Even though the laser and microwave can heat objects and increase the temp above the input power, it has a continuous input of power to replace the power emitted. It is not measured in the same way as a thermal source emitting energy, as the laser and microwave has power being added to it as it expends the power.
when I get poop in my teeth. when I get poop on my plates. Being able to have a portable bidet would help keep things all clean and shiny. I like this channel. I don't mean to smear crap on the internet.
I've been a manufacturing laser operator for 14 years and i can attest that the latest fiber lasers are indeed insane. at a mere 6kw you can easily cut through 1 inch steel plate.
That water flosser looks cool, but it's really bulky. What if we could attach it to the faucet? I bet you wouldn't even need to put a motor in it to get it up to pressure!
LED flashlights sort of do this since they emulate a black body source. Used to have one of those Nitecore lights and with great difficulty it could get to charring and smoldering paper.
@@josenobi3022 There was a recent paper with a misleading title. @Anton Petrov is usually a reasonable science communicator. His video on that paper was not so good. It left the impression that laser beams actually cast shadows under certain conditions. A green laser beam can cause electrons in a ruby to jump to a particular energy level which then emits some heat and drops to an intermediate energy level that is stable on the order of a millisecond. Electrons at that level can absorb blue light. Things that absorb light cast a shadow. At human time scales it looks and acts like the green laser beam can cast a shadow. [Edit: Found the name of Anton Petrov's channel. Used that instead of a vague description.]
another interesting thing, for the same reasons that lasers can heat things up beyond the "source temperature" they can ALSO COOL THEM DOWN. yes, cooling lasers. you should do a video on that!
Here is a question: Can we use fiber optic cables to carry the focused sunlight(maybe with multiple lenses) to somewhere else and direct all the light onto a single point. Can we achieve a higher temperature?
Hmm ... that's against my intuition 🤨 imagine we use a lens with an area of, lets say, 10 square meter, and focus all the light on a grain of sand (which is insulated within a thermos can by the way), then the grain gets so much more energy compared to its size Would it still not get hotter than the sun? Where does the focused energy go then?
well as it is emitting energy, and that energy is usually measured over an area not a point, so you can concentrate that energy by reducing the area that it is dissipating energy over. so yes you can focus a collimated beam of light and make it higher powered.
@@johng.1703 but you can't go on forever concentrating and at some point you are re-radiating all the power you are concentrating since radiation goes with the 4th power of temperature. I might not understand what you want to demonstrate though
2nd law has to deal with entropy NOT temperature, and it refers to an "isolated system". Temperature is a simple interpretation of entropy moving from hot sources to cold. What's your total system in the 10kW laser example?
Me and my girlfriend where talking in our workshop about if theoretically our 70w co2 laser could heat our room. My theory was the beam focused on a heat sink sort of thing may do something but I couldn’t find a definitive answer on how how the centre of the beam is. Roughly 3500c was what I was getting to but I’m going to watch the video now 😂
70 watts is still 70 watts. It could certainly heat up a heat sync, and likely melt it. But you'd still only get 70 watts of heat into the room. Your own body heat is more than that.
What happens if you get like a spherical array of those laser cutters or even stronger lasers, pointed them all inwards towards the direct centre of the sphere and then fire them at something in that centre point?
It'll likely vaporize quite rapidly. It's basically a lower power version of one of the proposed methods of igniting fusion. Fuel is inserted into a pellet and it gets hit with high power lasers from multiple directions; the blast wave of the shell vaporizing compresses the fuel to fusion conditions.
Fun fact: Because of the definition of temperature (which only makes sense in macroscopic systems, as it deals with the entropy concept) T=dQ/dS, in systems where there is a maximum energy there are states where temperature is negative. Additionally these negative temperature bodies always transfer heat to positive temperature bodies. A good example of a negative temperature system is a laser 🤯🤯🤯
Great observation! Before use, the phosphor has to be charged with visible light (e.g. sunlight), so that, when hit by infrared light, it releases the energy stored during the charging process
So is this what happens/process with the non-lethal weapon for crowd, control, etc.? I’m speaking of the one that causes the person to feel hot where it hits.
I think the rough answer is that the kinetic energy of the particles goes up faster than the speed. This is because the relativistic mass of the particles goes up with their speed. To reach the speed of light the particles would need to be infinitely heavy - which never happens. In a sense the energy creates extra mass. E = mc^2 comes in here somewhere, I think my explanation is basically correct, but probably no use the latest way of explaining it.
So if I understand it correctly. The laser just turns the light energy into heat energy at the point of impact. The total energy of the light energy will be more than the energy required to heat up the material by X amount. other will be lost in form of reflected light or other forms of energy. You literally said it. light has no temperature. so no paradox?
I'm not sure what I'm about to say is a fully valid explanation, but in that thermal radiation curve, the slice of it within the laser range is will make up X percent of the energy. If you instead drive just that frequency it is out of equilibrium with the black body curve and as the heat stochastically spreads out back into the black body distribution, the vibrating atoms will try to spread back into that black body curve instead of the one with a huge peak at that IR frequency. You have to overpump that one frequency enough to spread out over that whole black body spectrum to a point where the IR energy slice of the black body curve matches the incoming (which will never happen, but it will hit an equilibrium from the outgoing radiation cooling things). The ultraviolet catastrophe solution from quantum physics though means you can't easily just pump out higher frequencies indefinitely, it will start exponentially falling off with planck's distribution. The microwave I thought has a little bit different explanation with resonance with the water particles, but maybe it works out to the same thing.
youre actually mixing up some stuff here, the magnetron of an microwave is not around 100 degrees. or rather the electrons in it are extremely hot by being pumped by electromagnetic fields, about 80 000 K (although measuring this in temperature is kinda pointless), above this a magnetron should not heat up anything. not normally a concern obviously but quite different from the negative temperatures that lasers have.
"Honey, why is our electric bill 2 million dollars this month?" "I'm not sure babe but It's definitely not because of the 10Kw laser I just installed in the garage."
rose water.. great for mouthwash.. really helps to clean teeth out of debris. plain rose water.. not the stuff they use to remove makeup! very different products with the same name
Not being able to heat something hotter than the sun's surface using its emissions... Does that count focusing the sun's image through a lens or mirror?
7:34 doesn't that mean you can heat an object more assuming you focus all of it on a smaller object since a smaller object won't radiate the heat as fast right?
The second law is wrong. Heat pumps may not create thermal kinetic energy, but they do organise more joules of thermal kinetic energy against the natural heat gradient than they require in mechanical input to opperate. This effect, where their cop > 1, means that a heat pump lets you trade a relatively small kinetic input for a relatively large thermal potential gradient. Potential energy is a real and valid form of energy. If I can spend 100 joules of mechanical energy to establish 200 joules of thermal potential energy, then the second law is incorrect because I can lower the local entropy faster than entropy increases to supply me with power for my heat pump.
So then why can't we heat stuff above the sun temperature using lens since the sun is also not a simple Thermal system (with fusion continuously adding energy like the battery of your laser ) ? Why is there a limit to energy focus of the sun light through a lens but not with a laser that also has to obey optics law ?
Laser dust, aka metal dust. The exhaust is drawn into an air handler. If you want mars soil, ask for some laser dust. It's nearly the same density of air. Gets everywhere. Probably giving me Parkinson's in a few years.
Did you say that you cannot focus sunlight to a pinpoint that is hotter than the source? If I have a very large surface at 1000 C, and I focus the light (IR) to a pinpoint, the pinpoint will not be hotter than 1000 C?
@@DANGJOS You don't help anyone by just repeating the statement. The Stefan-Boltzmann Law works with an area, the magnification(in one direction) has an effect for the equilibrium of the heat transfer.
If you had a very big lens or focussing mirror you could theoretically concentrate the energy from the sun and create a temperature hotter than the sun’s surface.
No, that's the point he's trying to make. Even if you concentrated all the light from the sun onto a single point you still couldn't heat up an object hotter than the sun.
@@stevesethermaybe that's the point then. That you can't concentrate all the energy from the sun into a point. If you could do that, then yes you would get a higher temperature than the surface.
To be pedantic; single particles or atoms do not have a temperature. Temperature is an emergent phenomenon categorized by the aggregate motion of the particles in the system.
@@hehehahahmhmhm Bad grammar, no punctuation, misspelled words, yeah that checks out. You could have just gone to google and typed 'does a single atom have a temperature' instead of coming here to make a fool out of yourself.
@@hehehahahmhmhm They did not cool down single atoms; instead, they slowed them down (i.e., decreased their kinetic energy) to nearly zero velocity. The temperature refers to the collective of slowed-down atoms as OP said
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"Imagine if we shine ten million of them in the same spot". For some reason I was expecting an xkcd collab after that.
Lmao me too
YH. That would be something
Didn't they just do one about shining lots of lasers on the moon?
you would be disappointed , they couldn't be coherently added, different directions, different degrees of freedom.
"What if we tried more power?"
I Accidentally put my hand on some 800C Steel while using an oxyacetylene torch one. Sizzled like your 'assistant'
Been there. My fingers have additional contours
When I worked in a condensed matter physics lab, I touched a quartz tube recently heated by an oxy-hydrogen torch. Burned my thumb! Fortunately, it was only superficial.
I did this on accident also, my skin turned white. Luckily it was only a tiny spot and after the blister and new skin you can nearly notice it anymore. The funny thing about the experience for me is I didn't feel it at the second it happened, and the pain just got gradually worse after I realized. It probably got to peak pain about 10 minutes after. The body is strange the way it works. Pretty amazing really.
I was touching red hot pen springs for fun. Quite an experience! No pain, only parallel lines burnt into my fingers, pretty interesting way to modify fingerprints.
I touched a hot plate which was turned on, because i thought it was off.
I got near it first to test if its on, didnt feel the heat somehow (maybe it was going on and off and at that moment it was off), and to be sure that its off i touched it. Instantly retracted my hand.
This left a white powder on the surface of my hand. Luckily only the very top layer got burned to dust, and the below layers where fine.
In the end, it turned out that the entire clip was just an advertisement, even the part before it, and everything was just an opening or context to introduce the product.
The product had nothing to do with heat or energy transfer.
LASER = Light Amplification by Stimulated Emission of Radiation 🙂
Radiation really is 🤩 .
yes this sums up the whole video actually
@@BibhatsuKuiri thats what im trying to say.
GIF.
Stimulated 😍😍
Two different proceses: first the IR cameria is simply making an inference between light emission & temperature & its based up on limited IR spectrum, not the full light spectrum. Visible light has a correspondence with much higher temperatures than IR, but the thermal camera does not interprete white light with heat.
When you shine a high watt light source on a object that absorbs the light, the light stimulates the electrons in the object causing increase molecular viberations (ie heat).
"Imagine if we shine ten million of them in the same spot" National Ignotion facility has entered the chat.
One big issue I have with science communication is the oversimplification tends to always fall into epistemic fallacies. When you say things like "This curve is determined by Planck's Law" it implies it has agency or causal power, it conflates our knowledge of the universe with the actual mechanisms. Scientific laws are frameworks for understanding observations, not the "causes" of phenomena. A very common example is when people say a particle knows when it's being observed in a quantum system. Particles don't possess awareness or agency, it's is the act of measuring that interacts with a quantum system.
I don't mean to target this directly at The Action Lab, these are just thoughts I've had for some time now.
Nah, you're looking too deep into it. Anyone with basic education understands that it's not the Planck's Law that forces things to emit in a particular way, it's their emission spectrum is distributed according to some law. Also it's appropriate to say exactly as stated in the video, because he was talking about the CURVE, which is a mathematical object described by the Planck's Law. It doesn't exist in reality as well.
@@arseniixmost people with basic education dont know ABOUT planck's law
Sixty Symbols did a video on this topic 11 years ago called "Negative Temperatures are HOT" referring to negative absolute temperatures rather than negative Fahrenheit or Celsius. You can also think of them as beyond infinite temperature. Heat will _always_ move from a negative temperature region into a positive temperature region no matter how hot the positive temperature is. You can literally heat the Sun a minuscule amount by shining a laser at it.
Yes! The Action Lab also has a video on this
@@DANGJOSwhich video?
@@blueslime5855 If you search "what happens if you focus a laser Action Lab" you should find it
I'm outside using a standard laser pointer but I'm trying my best to help make winter just a little more mild this time. You're welcome guys!
@@FlameMage2 This winter has been super mild here in Texas. Keep up the good work!
2:39 crazy vending machine they got there.
This is a great video, I design laser engraving systems. We go down to spots with a size of a few microns to get some enormous power density. This is a great basic video explaining some of the phenomenon
comically small sun
I learned yesterday that we figured out what was diamonds were by vaporizing them, and then doing experiments to see what the gas was! This was in the 1700s!
One of the methods they used was simply lenses. How crazy is that. I've seen people burn rocks, but diamonds just using the sun is crazy to me.
He should do this himself.
Makes me appreciate glass. Where would science be without it. They used glass lenses to vaporize diamond to capture the gas in glass vessels to weigh the gas! Then used glass beakers to do the tests.
@@dianapennepacker6854 burning diamonds is nothing different than burning graphite
What confuses me is the sun is continually adding energy - it's an ongoing nuclear reaction continuously pumping more energy out in the EM spectrum - it's not coherent light like a laser, but there's not only the blackbody light radiation coming from the sun, but all of the photons generated by nuclear fusion as well - so it should theoretically be able to do what a laser pointer does a trillion times over.
The light coming from the sun is not the light emitted in the fusion reactions in the core. Light takes thousands of years to get out of the core to the surface.
not true, coherence matters, the sun radiation can not heat up a body to temperatures higher than the sun surface temperature of 5000 °K otherwise it would contradict thermodynamics second law. A laser pointer can go higher given the absorbing object is insulated enough.
looks like the channel owner removes comments that he doesn't like :/
for that same reason we can not infer what really is the temperature of the sun, as the law we use to calculate temperature from radiation only applies to objects in thernal equilibrium.
You can heat up the filament in your toaster to ~800°C even tho the steam in your powerplant is only around 400°C
The principle only applies to using lenses and mirrors and a hot body.
Still getting my head round this one!
The laser light is transferring energy. Whatever the laser is shining on is accumulating that energy so it is a question of time and energy not simply energy.
The video feels incomplete, light goes in and the light-matter interaction is where all the black box magic lies, but this video didn't explain that. Would that same laser melt me up like it did the metal? Why or why not? How does the energy of the laser get converted into thermal energy? The material absorbs it, and how much it's absorbed is material-dependent, why? What's the difference between a continuous wave laser and a pulsed laser?
Note to self: Never be an assistant at ActionLab! 🤣
😅😂 But you can send him cool stuff to experiment with. I did.
@@westonding8953 Your hand?! 😉
before i watched u i always got c- or d- in school but after watching ur vids for a few years now ive been getting a- and a+! thank you!
Hi Bob, I am your teacher, and I don't remember you getting anything higher than F, ever.
5:27 Question: how does LASER compare to SOLAR radiation? I think of the sun as emitting all manner of spectrum, based on something somebody said about Parker space probe data result ... What is the EM difference of focused LASER vs solar, thinking a minuscule Earth sized critter is in a straight line to the solar radiance, thus reasonably coherent beams of photons??? Just wondering 'bout Black Body radiation vs EM ... the rest was very educational, but caused me this question about exceeding limits. If a lens focused a particular wavelength, continually powered by the sun, how would the physical interaction effect result differently, laser vs specific solar radiation? (if the lens were focused in outer space without pesky atmospheric light scattering annoyance 😬) EDIT: I will search "what happens if you focus a laser Action Lab" based upon a comment.
Dude, what were you eating!? 4:52
Man that laser is so satisfying seeing it cut that thick metal like it's nothing! This is a great approach to heating things up. The way lasers & magnetrons heat things up reminds me of how Tesla considered we could destroy anything if we manipulate the objects frequency in order to vibrate it until it breaks apart. So take that but shift it over to an electromagnetic device that manipulates a large amount of electrical energy and aim it at a focused point and allow the electromagnetic frequencies to interact with that object until it heats it up
Remember this is also related to negative temperature, which he's also done a video on.
Thanks! I needed this video to explain how that little laser of only a couple of milliwatts somehow managed to heat the parts of the radiometer all the way to incandescence! 🔥
You can heat metallic things with "radio wave" frequencies using induction furnace...
A laser differs from a regular light in the fact that it is monocromatic, coherent, and directional.. so, how can a laser be able to heat something to infinity while a concentrated regular light only can heat something up till it gets to the temperature of the source of that light?? What is the difference in the business end of the light, when impacts a surface?... I wonder..
This is exactly my question. The video didn't really explain why laser light is different. Perhaps the coherence of the light is the big difference here? You could surely filter out all the frequencies of sunlight to a single frequency, and concentrate it.... but you couldn't make it coherent.
@@stevesether It kept me thinking, could it be that "light transferring energy" behave as heat or electric current?, where you have "temperature" and "heat" or "voltage" and "current" respectively.. let's say.. an impulsory force and an ammount of energy being transfered.. once the force is in equilibrium you can't "push" anymore energy to the other side... Laser might have, or be able to get, an arbitrarily high level of "force" to "push" while for sunlight or any random white light the "force" is only as strong as for the source of that light, so it cannot achieve higher temperatures. In such a case, what would be the "voltage" (or pressure making a fluids analogy) for the light? I don't know..
Even though the laser and microwave can heat objects and increase the temp above the input power, it has a continuous input of power to replace the power emitted.
It is not measured in the same way as a thermal source emitting energy, as the laser and microwave has power being added to it as it expends the power.
when I get poop in my teeth.
when I get poop on my plates.
Being able to have a portable bidet would help keep things all clean and shiny.
I like this channel. I don't mean to smear crap on the internet.
I've been a manufacturing laser operator for 14 years and i can attest that the latest fiber lasers are indeed insane. at a mere 6kw you can easily cut through 1 inch steel plate.
That water flosser looks cool, but it's really bulky. What if we could attach it to the faucet? I bet you wouldn't even need to put a motor in it to get it up to pressure!
I think the toothbrush needs a laser to blast the plaque away
I used to design trumpf machines. they're good
LED flashlights sort of do this since they emulate a black body source. Used to have one of those Nitecore lights and with great difficulty it could get to charring and smoldering paper.
Ahhh...the red hot nickel ball days😢
Light can cast shadow, therefore there are limits to laser concentration.
wtf do you mean
@@josenobi3022 There was a recent paper with a misleading title.
@Anton Petrov is usually a reasonable science communicator. His video on that paper was not so good. It left the impression that laser beams actually cast shadows under certain conditions.
A green laser beam can cause electrons in a ruby to jump to a particular energy level which then emits some heat and drops to an intermediate energy level that is stable on the order of a millisecond. Electrons at that level can absorb blue light. Things that absorb light cast a shadow. At human time scales it looks and acts like the green laser beam can cast a shadow.
[Edit: Found the name of Anton Petrov's channel. Used that instead of a vague description.]
@@hamjudo wouldn't that mean the ruby is casting the shadow ? Even then I don't understand the "therefore there are limits to laser concentration"
That CD in the microwave was so cool. I'll have to try that at home.
another interesting thing, for the same reasons that lasers can heat things up beyond the "source temperature" they can ALSO COOL THEM DOWN. yes, cooling lasers. you should do a video on that!
Look up water jet laser cutting. Gets pretty weird but very awesome.
The amount of energy pumped into the medium that releases the light is far greater than the energy imparted to the object by the laser light.
Nice Open Sauce tshirt, hope I can make it one year
Here is a question: Can we use fiber optic cables to carry the focused sunlight(maybe with multiple lenses) to somewhere else and direct all the light onto a single point. Can we achieve a higher temperature?
Hmm ... that's against my intuition 🤨
imagine we use a lens with an area of, lets say, 10 square meter, and focus all the light on a grain of sand (which is insulated within a thermos can by the way), then the grain gets so much more energy compared to its size
Would it still not get hotter than the sun? Where does the focused energy go then?
If the heat radiation can get in (into the thermos) then it can get out. As the grain of sand gets hotter, it radiates energy away.
How does matter absorb energy?
Your channel is one of the few that really enjoys the quality of content. Keep it up!😆🎽🙉
If I rub my hands, both get hotter than my hands! Have I violated any law of thermodynamics, or is it just work used to increase the thermal energy?
Mechanical work converted to heat by friction. Just like what brakes do.
I love OSH cut!
Lasers can't heat anything up past the temperature of an electron, which is the most energetic particle we can reliably generate with lasers.
well as it is emitting energy, and that energy is usually measured over an area not a point, so you can concentrate that energy by reducing the area that it is dissipating energy over.
so yes you can focus a collimated beam of light and make it higher powered.
at one point you hit the diffraction limit for a given wavelength
@@omblauman umm a single wavelength of light will diffract to a single wavelength of light.
@@johng.1703 yes and you can't go lower and increase power density infinitely
@@omblauman what are you going on about? focusing a single wavelength just means concentrating more energetic particles into a single point.
@@johng.1703 but you can't go on forever concentrating and at some point you are re-radiating all the power you are concentrating since radiation goes with the 4th power of temperature. I might not understand what you want to demonstrate though
2nd law has to deal with entropy NOT temperature, and it refers to an "isolated system". Temperature is a simple interpretation of entropy moving from hot sources to cold. What's your total system in the 10kW laser example?
Me and my girlfriend where talking in our workshop about if theoretically our 70w co2 laser could heat our room.
My theory was the beam focused on a heat sink sort of thing may do something but I couldn’t find a definitive answer on how how the centre of the beam is.
Roughly 3500c was what I was getting to but I’m going to watch the video now 😂
70 watts is still 70 watts. It could certainly heat up a heat sync, and likely melt it. But you'd still only get 70 watts of heat into the room. Your own body heat is more than that.
Lasers hotter than infinity, was one of your previous videos I believe, so I kinda expected this result!
Great video!
Should have gone to the styro Pyro that guy can build a laser
When two coherent laser beams destructively interfere with each other (like in the LIGO detector), where does the energy go?
It goes to the Bahamas
As always, Great video.
So if i understand that right: You can technically focus a laser as tight as a single Hydrogenatom and get it infinetly hot?
What happens if you get like a spherical array of those laser cutters or even stronger lasers, pointed them all inwards towards the direct centre of the sphere and then fire them at something in that centre point?
I believe that's the principle of the fusion reactor at NIF
It'll likely vaporize quite rapidly. It's basically a lower power version of one of the proposed methods of igniting fusion. Fuel is inserted into a pellet and it gets hit with high power lasers from multiple directions; the blast wave of the shell vaporizing compresses the fuel to fusion conditions.
@@DW-indeed no, the temperature of the NIF target is high (~10^7 K) but many orders of magnitude below the laser wave temperature
Fun fact: Because of the definition of temperature (which only makes sense in macroscopic systems, as it deals with the entropy concept) T=dQ/dS, in systems where there is a maximum energy there are states where temperature is negative. Additionally these negative temperature bodies always transfer heat to positive temperature bodies. A good example of a negative temperature system is a laser 🤯🤯🤯
I guess the infrared temperature sensor has provision for ignoring emission lines, so it just ignored the laser light being shone at it.
I love lasers, pls more things abt them if possible
The same principle is used in cooling lasers
Wait. How does the infrared sensor plate work? It absorbed the infrared and emitted red. Things don't flouresce a higher energy light...
Great observation! Before use, the phosphor has to be charged with visible light (e.g. sunlight), so that, when hit by infrared light, it releases the energy stored during the charging process
This is the same situation in a microwave oven. The waves are not transferring heat, they are creating heat in the object.
So is this what happens/process with the non-lethal weapon for crowd, control, etc.? I’m speaking of the one that causes the person to feel hot where it hits.
I am confused, wouldn’t there have to be a limit to temperature, otherwise the particles would end up vibrating faster than the speed of light.
I think the rough answer is that the kinetic energy of the particles goes up faster than the speed. This is because the relativistic mass of the particles goes up with their speed. To reach the speed of light the particles would need to be infinitely heavy - which never happens. In a sense the energy creates extra mass. E = mc^2 comes in here somewhere, I think my explanation is basically correct, but probably no use the latest way of explaining it.
Is electricity the same ? Does electricity have a temperature ? Is there a maximum temperature a certain voltage can reach ?
So if I understand it correctly. The laser just turns the light energy into heat energy at the point of impact. The total energy of the light energy will be more than the energy required to heat up the material by X amount. other will be lost in form of reflected light or other forms of energy. You literally said it. light has no temperature. so no paradox?
Yea how do you cut through steel and then not cut trough whatever is behind it for some great distance?
I know it doesn't need to be said, but lasers are really cool!
I'm not sure what I'm about to say is a fully valid explanation, but in that thermal radiation curve, the slice of it within the laser range is will make up X percent of the energy. If you instead drive just that frequency it is out of equilibrium with the black body curve and as the heat stochastically spreads out back into the black body distribution, the vibrating atoms will try to spread back into that black body curve instead of the one with a huge peak at that IR frequency. You have to overpump that one frequency enough to spread out over that whole black body spectrum to a point where the IR energy slice of the black body curve matches the incoming (which will never happen, but it will hit an equilibrium from the outgoing radiation cooling things).
The ultraviolet catastrophe solution from quantum physics though means you can't easily just pump out higher frequencies indefinitely, it will start exponentially falling off with planck's distribution.
The microwave I thought has a little bit different explanation with resonance with the water particles, but maybe it works out to the same thing.
youre actually mixing up some stuff here, the magnetron of an microwave is not around 100 degrees. or rather the electrons in it are extremely hot by being pumped by electromagnetic fields, about 80 000 K (although measuring this in temperature is kinda pointless), above this a magnetron should not heat up anything. not normally a concern obviously but quite different from the negative temperatures that lasers have.
temperature - is paremeter of body. Laser or elecrons has no body so temperature not applicable to it at all
I love watching dirk nowitzki doing science
A single term would've been enough to explain the difference: Thermal radiation and it's opposite non-thermal radiation.
"Honey, why is our electric bill 2 million dollars this month?" "I'm not sure babe but It's definitely not because of the 10Kw laser I just installed in the garage."
How is this connected with this weird negative temperature of lasers you came up with in an older video?
What if you split blackbody light using a prism?
Can you get blind from infrared light, that you can't see?
rose water.. great for mouthwash.. really helps to clean teeth out of debris. plain rose water.. not the stuff they use to remove makeup! very different products with the same name
Not being able to heat something hotter than the sun's surface using its emissions... Does that count focusing the sun's image through a lens or mirror?
Nice video. 🖖
1:00 "well light doesn't have a temperature" that's the end of the video.
exactly
@@akeslav exactly wrong
Can you reproduce Herschel’s experiment with that infrared camera please?
I didn’t know light didn’t have a temperature. That’s actually been something I was wondering
7:34 doesn't that mean you can heat an object more assuming you focus all of it on a smaller object since a smaller object won't radiate the heat as fast right?
I want to see more of that super lazer is that what comes out of superman
The second law is wrong. Heat pumps may not create thermal kinetic energy, but they do organise more joules of thermal kinetic energy against the natural heat gradient than they require in mechanical input to opperate.
This effect, where their cop > 1, means that a heat pump lets you trade a relatively small kinetic input for a relatively large thermal potential gradient.
Potential energy is a real and valid form of energy. If I can spend 100 joules of mechanical energy to establish 200 joules of thermal potential energy, then the second law is incorrect because I can lower the local entropy faster than entropy increases to supply me with power for my heat pump.
Crazy that when you light a match, it gets hotter than the surrounding environment
Now reenact that scene from James Bond. You know the scene. The one where Mr. Bond almost lost his...
Well you know.
That is why we also have laser cooling. Because lasers are magic.
Think you and Styropyro should collab
So then why can't we heat stuff above the sun temperature using lens since the sun is also not a simple Thermal system (with fusion continuously adding energy like the battery of your laser ) ? Why is there a limit to energy focus of the sun light through a lens but not with a laser that also has to obey optics law ?
Is this also related to conservation of etendue?
me watching the laser cut steel like butter then this guy suddenly tell us about electric toothbrush
Peak promotion
So where exactly is all this vaporized metal condensing?
Laser dust, aka metal dust. The exhaust is drawn into an air handler. If you want mars soil, ask for some laser dust. It's nearly the same density of air. Gets everywhere. Probably giving me Parkinson's in a few years.
THANK YOU, ACTION LAB! DOGE COIN GOING UP BABYY!!🚀🚀
Did you say that you cannot focus sunlight to a pinpoint that is hotter than the source?
If I have a very large surface at 1000 C, and I focus the light (IR) to a pinpoint, the pinpoint will not be hotter than 1000 C?
Yes, no hotter than 1000.
@@nuclearmedicineman6270 How would the pinpoint radiate the excess energy away?
No, you can't get it hotter than 1000C with just lenses and mirrors.
@@DANGJOS You don't help anyone by just repeating the statement. The Stefan-Boltzmann Law works with an area, the magnification(in one direction) has an effect for the equilibrium of the heat transfer.
Conservation of Etendue
One is a stationary source of energy. On the other case you are continuously pumping and dumping energy.
So the best strategy is the pump and dump scheme, got it
This was very interesting ❤❤❤❤❤
So we can safely assume that Clausius and Thomson did not own lasers or microwave ovens
Weird how the universe is. Unrelated to this I had bought a radioscope the other day. Testing my LEDSs of different wavelength.
If you had a very big lens or focussing mirror you could theoretically concentrate the energy from the sun and create a temperature hotter than the sun’s surface.
No, that's the point he's trying to make. Even if you concentrated all the light from the sun onto a single point you still couldn't heat up an object hotter than the sun.
@@stevesethermaybe that's the point then. That you can't concentrate all the energy from the sun into a point. If you could do that, then yes you would get a higher temperature than the surface.
@@stevesether yes I see now - thanks.
Let's 'Supersize' this and come out with BBQ in seconds.... cheers
To be pedantic; single particles or atoms do not have a temperature. Temperature is an emergent phenomenon categorized by the aggregate motion of the particles in the system.
then how a scientist got noble prize by inventing a method to cool down SINGLE ATOMS to just a few milli Kelvin above absolute zero
@@hehehahahmhmhm Bad grammar, no punctuation, misspelled words, yeah that checks out. You could have just gone to google and typed 'does a single atom have a temperature' instead of coming here to make a fool out of yourself.
@@hehehahahmhmhm They did not cool down single atoms; instead, they slowed them down (i.e., decreased their kinetic energy) to nearly zero velocity. The temperature refers to the collective of slowed-down atoms as OP said
@@lumarans30 you are both wrong.
@@lumarans30reducing movements is laterally what is lowering temperature. they are the same thing